The effect of Ganoderma lucidum polysaccharides on male lamb liver immunity based on RNA-seq technology

In order to study the effect of Ganoderma lucidum polysaccharides on the liver immune function of weaned Chuanzhong black goat lambs, 48 weaned Chuanzhong black goat males aged 40-50 days and weighing about 14 kg were randomly divided into 4 groups, namely blank control（CON） group, low-dose（LGLP） group, medium-dose（MGLP） group, and high-dose（HGLP） group, each with 12 animals. During the experiment, 0,200,400,800 mg/kg of Ganoderma lucidum polysaccharides（calculated as dry matter） were added to the basic diets of the CON,LGLP,MGLP and HGLP groups. The pre-feeding period was 7 days and the formal trial period was 56 days. After the experiment, each group randomly selected 6 Chuanzhong black goats for slaughter, and separated their livers for liver immune index determination and transcriptome sequencing; and GO biological process and KEGG metabolic pathway analysis of differentially expressed genes were performed. The results showed that compared with the CON group, MGLP group（addition of 400 mg/kg Ganoderma lucidum polysaccharides） could significantly increase the liver IL-6,TNF-α and IL-1β levels in Chuanzhong black goats（P＜0.05）. The MGLP group had the best immune effect, so liver samples from the MGLP group and CON group were selected for transcriptome seqencing analysis. Transcriptome sequering analysis results showed that the differentially expressed genes between the MGLP group and the CON group were significantly enriched in four immune-related pathways: antigen processing and presentation, T cell receptor signaling pathway, chemokine signaling pathway, and MAPK signaling pathway（P＜0.05）. A total of 19 differentially expressed genes were screened from 4 immune-related pathways. 11 differentially expressed genes including CCL5,CⅡTA,and LOC102183314 were significantly up-regulated（P＜0.05）,and 8 differentially expressed genes such as DUSP1,MYC,and LOC102177850 were significantly down-regulated（P＜0.05）. The results suggested that the addition of 400 mg/kg Ganoderma lucidum polysaccharides can significantly improve the liver immune function of weaned Chuanzhong black goat lambs, and regulate the expression of related genes in those pathways antigen processing and presentation, T cell receptor signaling pathway, chemokine signaling pathway and MAPK signaling pathway, for the adjustment of the immune function of lamb liver.